I currently have the factory muffler on my 99 sport, and have noticed a few small rust holes in it. I am contemplating whether a new muffler, possibly flowmaster, would decrease full consumption and possibly increase acceleration to any degree? I'm not big on super loud units either, something mellow, slightly more aggresive than stock would suit me well. any comments?

Little, if any change with just a muffler...

I run a Magnaflow 14" 4x9 oval muffler and it sounds good. Freeing up exhaust also frees up power. I paid 49$ for mine on Amazon. You can go with a longer one if you want. I have a turn down on mine.

alright, i will rule out the effienciency factor, so perhaps when i got a few extra bucks to blow might give it a shot just because.
does anyone have pics where they have ran an aftermarket tailpipe other than the factory location?

i think rustys sells a bigger pipe on their website and if im not mistaken its a direct fit but not sure on that.

I got a magnaflow muffler. It increased my mpgs by two. And feels like throttle response is better.

Did a turndown, then side exit.

wow...sounds tempting, i average about 12-13 with my 31s

@djb383, looks good man thats similar to what i was thinking

Check the vendor section for a 2.5" kit I offer.

Typically freeing up the exhaust will give a little bit better mpg but how much you will see varies. People have claimed anywhere from .2 - 2 mpg. When I did the exhaust on my old 90 XJ I saw about 1.5 mpg and it was easier to pull hills.

Ummm if you want i can make a video for you of my setup with a turn down

Ya mine went from 15 to 17 city

I'm pretty happy with my Dynomax Cat back system, its not super loud, slightly more aggressive than stock but quiet while idling. Haven't noticed a difference in performance, and my truck generally gets the same mpg no matter how I drive it..

i put a custom made muffler to 4.0 grand cherokee. sounds little louder but throttle response is significantly better.

I would love to see that as well